A processor may be in an active state of operation, e.g., while performing a processing operation; or an inactive state of operation, in which the processor may consume a reduced amount of electrical power compared to the electrical power consumed by the processor when in the active state of operation.
At least part of the power consumed by the processor in the inactive state of operation may be due to a power leakage through one or more logic elements of the processor, e.g., combination and/or sequential logic elements. For example, the logic elements may include a plurality of transistors, which may consume power even when in an inactive or “off” state of operation, e.g., due to an electric field between the transistor-source and transistor-drain. The amount of power consumed by the processor may increase if the processor resides in the inactive state of operation during relatively long time periods. In some applications, particularly those that operate on battery power, it may not be desirable for excessive power to be consumed by a processor. Moreover, excessive power consumption is some electronics systems may cause heat to be generated, which may be undesirable (e.g., in a laptop computer).
Prior art techniques for managing power consumption in a processor during an inactive state include increasing a threshold voltage applied to one or more transistors of the processor. However, while increasing the threshold voltage may reduce power leakage, it may have the undesirable effect of reducing performance.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function.